Different models have been proposed to explain the origin and physical nature of QPOs in X-ray binaries (XRBs). The study of LF–QPOs provides an indirect way to understand the accretion flow around the compact object in XRBs. The relativistic precession model (RPM), based on general relativity and proposed by [1]}, explains the origin and evolution of LF–QPOs and a few HF–QPOs in neutron star X-ray binaries. According to this model, QPOs originate as a result of the nodal precession, periastron precession, and Keplerian motion, of a luminous blob of material in the accretion flow around the compact object. [2]} extended the model proposed by [1]}, considering the complete inner flow instead of a luminous blob. The authors tried to demonstrate the origin of LF–QPO and the noise linked to them. Later [4]} extended this model to black hole X-ray binaries.
